1. Field of the Invention
This invention pertains to a system of counterfoil binding to be used for assembling documents such as loose sheets which are to be classified or filed.
2. Description of the Related Art
Various devices making it possible to classify such documents are well known; among them: slide file, ring file, plastic wallet folder, files with fasteners and jaws; rod-, thread- or gummed back-bindings.
All these devices have, to different degrees, various drawbacks; they are cumbersome or not handy, require special tools, do not make it possible to add in extra sheets, etc.
In other devices, documents are glued on counterfoils fastened together in a rigid cover. So patent FR No. 1.581.616 describes a counterfoil device consisting of strips which are covered, on one of their sides, with adhesive material; each strip can be folded into two parts, one of which is provided with a protective strip which covers the adhesive. The strips are glued one on the other to form a counterfoil. The parts provided with a protective strip can receive a sheet, to be glued after the strip has been removed. This device has a serious drawback: when the whole is tightened in a rigid cover, owing to the strip being folded, the excessive thickness of the parts of the strips on which the sheets to be classified are glued only makes it possible to classify a small number of documents.
In patent FR No. 740,536 a number of counterfoils are provided, which are bound like a book, and on each of which a loose sheet can be fastened (for instance by a glueing process). This device, too, has the following serious disadvantage: as each sheet is glued on part of the surface of each counterfoil, this increases the thickness of the whole in the glueing area, proportionally to the number of glued sheets, which very substantially limits the capacity and advantage of this type of device.